CN101705436A - Duplex stainless steel - Google Patents
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- CN101705436A CN101705436A CN200910134128A CN200910134128A CN101705436A CN 101705436 A CN101705436 A CN 101705436A CN 200910134128 A CN200910134128 A CN 200910134128A CN 200910134128 A CN200910134128 A CN 200910134128A CN 101705436 A CN101705436 A CN 101705436A
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Abstract
The invention relates to a duplex stainless steel, which comprises the following components in percentage by weight: 20.0 to 22.0 percent of Cr, 1.9 to 2.3 percent of Ni, 0.2 to 1.0 percent of Mo, 1.0 to 2.0 percent of Mn, 0.1 to 0.2 percent of N and the balance of Fe and inevitable elements. By substituting the partial high-valent nickel element with low-valent Mn and N elements, the duplex stainless steel can greatly decrease the cost of the duplex stainless steel and ensure better corrosion resistance and hot and cold workability of the duplex stainless steel obtained by smelting. Compared with the typical duplex stainless steel 2205 steel, the edge crack amount of the duplex stainless steel provided by the invention is obvious lower. In the duplex stainless steel provided by the invention, a certain amount of Cu element also can be added to further improve the hot and cold workability of the stainless steel, further decrease the rate of edge cracks appearing in a hot rolling process of the stainless steel and offers the duplex stainless steel better corrosion resistance than 304 steel and 316L steel.
Description
Technical field
The present invention relates to a kind of duplex stainless steel, relate in particular to the high erosion-resisting ferrite austenite duplex stainless steel of a kind of low cost, belong to the stainless steel field of metallurgy.
Background technology
Existing 304 steel and 316L steel have all obtained being extensive use of aspect a lot of because of its outstanding erosion resistance, processibility and weldability.
A kind of ferrite austenite duplex stainless steel is disclosed respectively in the Chinese patent application 200480005769.7,200580038074.3,200610022589.0 and 200780000957.4, but, in the disclosed duplex stainless steel of above-mentioned patent application, the content of Mo element and Ni element is all than higher, because Mo element and Ni element etc. all belong to high valence elements, correspondingly also cause stainless cost too high, limited stainless steel application in some aspects.Therefore, present research is devoted to develop the ferrite austenite duplex stainless steel that low precious metal content has good cold and hot working simultaneously always.
Chinese patent application 200580045052.X discloses a kind of low nickel duplex stainless steel with excellent corrosion resisting property, wherein, Ni content in the duplex stainless steel can be reduced in the scope of 1.0-3.0%, simultaneously the CPT (critical pitting temperature) of this duplex stainless steel is reached more than 20 ℃.But still there are following problems in the disclosed duplex stainless steel of this patent application: 1, still contain more Ni element in the composition of this duplex stainless steel, its cost still has certain decline space; 2, in order to adjust the metal flow rate, reduce the Ni constituent content simultaneously, so that reduce cost, added more Mn element in this duplex stainless steel,, improved the thermoforming performance of duplex stainless steel simultaneously to substitute the Ni element, but, because it is higher that the content of Mn element compares, will cause Mn to combine and form MnS, and then cause the corrosion resisting property of duplex stainless steel and thermoforming performance to descend with S.
Can learn according to above-mentioned analysis, though the ferrite austenite duplex stainless steel of more low nickel content occurred, its cost is than 304, the 316L stainless steel has had bigger decline, but nickel content still has certain decline space, and, also few for the research report of duplex stainless steel at present, especially less for the research report of the cold and hot working performance of duplex stainless steel, therefore, study various elements for duplex stainless steel cold and hot working Effect on Performance, acquisition has better corrosion-proof wear performance, and the duplex stainless steel that has higher cold and hot working performance simultaneously again is still one of this area problem demanding prompt solution.
Summary of the invention
For solving the problems of the technologies described above, the object of the present invention is to provide a kind of duplex stainless steel, it belongs to a kind of low-cost corrosion-resistant steel, under the prerequisite of corrosion-resistant, the wear resisting property that guarantees duplex stainless steel and other mechanical properties, by adjustment and control, obtain that a kind of cost is low, the duplex stainless steel of cold and hot working excellent property to the stainless steel composition.
For achieving the above object, the invention provides a kind of duplex stainless steel, by weight percentage, its one-tenth is grouped into and comprises:
Cr:20.0-22.0%, Ni:1.9-2.3%, Mo:0.2-1.0%, Mn:1.0-2.0%, N:0.1-0.2%, all the other are Fe and inevitable element.
According to specific embodiments of the present invention, preferably, by weight percentage, stainless one-tenth provided by the invention is grouped into and can also comprises: below the S:0.0025%, below the P:0.035%.
According to specific embodiments of the present invention, preferably, by weight percentage, during being grouped into, stainless one-tenth provided by the invention can also contain Si, and its content is preferably below 2.0%.
According to specific embodiments of the present invention, preferably, by weight percentage, during being grouped into, stainless one-tenth provided by the invention can also contain Cu, and its content is preferably at 0.7-1.0%.
According to specific embodiments of the present invention, preferably, by weight percentage, during being grouped into, stainless one-tenth provided by the invention can also contain B, and its content is preferably at 0.0028-0.0043%.
Particularly, the effect of various elements of the present invention and preferred become to be grouped into can for:
Carbon: C is to increasing the favourable element of intensity of material on the solution strengthening principle, but C is excessive, can on ferritic-austenitic phase crystal boundary with to the favourable element of solidity to corrosion, combine, for example, reduce crystal grain chromium content on every side, thereby cause the corrosion proof reduction of stainless steel as the carbide forming element of Cr, therefore, for the solidity to corrosion that maximizes, preferably, the content of C is being suitable below 0.03% generally.
Nitrogen: in duplex stainless steel, N is the same with Ni all to be to the bigger element of austenite phase stabilization contribution, and the increase of N content, also can attach corrosion proof raising and stainless high strength; But N too high levels, will reduce stainless hot workability, thereby cause the reduction of casting yield, opposite N content is low excessively, just guaranteeing to balance each other must corresponding reduction Cr and the content of Mo, and can and guarantee that aspect such as weld part intensity bring adverse influence in the stable phase balance, therefore, preferably, N content is suitable at 0.1-0.2% generally.
Manganese: in order to reconcile molten steel (molten soup) degree of mobilization, the content of Mn is comparatively suitable about 1.5%, but during the Mn too high levels, can reduce the high temperature scale resistance of duplex stainless steel, also can combine simultaneously and form MnS with the S in the steel, thereby cause corrosion proof reduction, also can reduce stainless hot workability simultaneously, cause the limit to split the raising of incidence, therefore, the content of Mn is being suitable below 2% generally, and preferably, Mn content is generally at 1.0-2.0%.
Chromium: Cr is the same with Mo all to be ferrite stabilizers, its to the ferritic phase in the duplex stainless steel guarantee play a major role, and Cr guarantees the necessary element of stainless solidity to corrosion, the content that increases Cr can improve stainless solidity to corrosion, but balance each other for keeping simultaneously, need to increase the content of Ni, therefore, in order to keep balancing each other of duplex stainless steel, guarantee that simultaneously stainless solidity to corrosion is better than 304 steel and 316L steel, preferably, the content of Cr is suitable at 20.0-22.0% generally.
The same ferrite stabilizer that all belongs to Cr of molybdenum: Mo also is simultaneously that powerful solidity to corrosion improves element, and the effect that particularly improves anti-pitting attack and crevice corrosion performance is more obvious; But the shortcoming that the Mo too high levels also can bring the stainless steel shock-resistance to descend, therefore, preferably, the content of Mo is suitable at 0.2-1.0% generally.
The same austenite phase stabilizing element that all belongs to Mn, N of nickel: Ni plays a major role in mutually at the austenite of guaranteeing duplex stainless steel; In order to save cost, need to reduce the content of the more expensive Ni of price, (for example Mn and N) replaces Ni with other austenite phase forming element, but excessively reduces Ni content, just needs the content of excessive raising Mn and N, can reduce the solidity to corrosion and the hot workability of duplex stainless steel like this, perhaps, be difficult to guarantee that duplex stainless steel has the solidity to corrosion that is better than the 316L steel, therefore along with the minimizing of Cr, Mo content, preferably, the content of Ni is suitable at 1.9-2.3% generally.
Phosphorus: P is segregated among crystal boundary or the phase boundary, can cause the solidity to corrosion of duplex stainless steel and anti-flexible to reduce, and therefore, the content of P should be low more good more, considers the efficiency of refinery practice, and P content is being suitable below 0.035% generally.
Sulphur: S worsens stainless hot workability easily, and can reduce stainless solidity to corrosion because of the formation of MnS, therefore, S content also should be low more good more, its scope is comparatively suitable below 0.0025%.
Silicon: for deoxidation or in order to play the effect of ferritic phase stabilizing element, can in duplex stainless steel, add a certain amount of Si, but Si content is when too much, can reduce mechanical characteristicies such as stainless related impelling strength, therefore, preferably, Si content is comparatively suitable below 2.0%.
Copper: in stainless steel, add the performance that a certain amount of Cu can improve the stainless steel atmospheric corrosion resistance, can increase simultaneously the intensity of steel, simultaneously, Cu has austenitic and turns about 40% of usefulness into, and can improve stainless cold-forming property, but the Cu too high levels can cause stainless forgeability obviously to descend, therefore, preferably, Cu content is comparatively suitable in the scope of 0.5-1.0%, and more preferably, its content is 0.7-1.0%.
Boron: B belongs to non-common element, still, adds the performance that a certain amount of boron can improve the stainless steel intergranular corrosion resistance, improves thermoplasticity, improves hot workability, and preferably, the content of B is comparatively suitable at 0.0028-0.0043%.
The preparation of duplex stainless steel provided by the invention can adopt stainless steel field of metallurgy preparation method commonly used at present to carry out, and the technology that for example adopts electrosmelting-AOD argon oxygen refining-Ladle bottom blowing adjustment to handle is prepared.
The present invention is by with at a low price manganese, the nitrogen unit high price nickel element of instead of part usually, can reduce the cost of duplex stainless steel greatly, simultaneously still can guarantee to smelt the duplex stainless steel that obtains and have solidity to corrosion and cold and hot working performance preferably, than typical duplex stainless steel 2205 steel, the limit amount of splitting of duplex stainless steel provided by the invention obviously reduces.
In duplex stainless steel provided by the invention, can also be by adding certain amount of Cu, further improve stainless cold and hot working, further reduce stainless steel and the probability that the limit is split in course of hot rolling, occurs, duplex stainless steel is had be better than the corrosion resisting property of 304 steel and 316L steel.
Duplex stainless steel provided by the invention has good solidity to corrosion and cold and hot working performance, especially hot workability, can substitute 304 and type of stainless steel such as 316L; Simultaneously, duplex stainless steel provided by the invention can make it that better performance is arranged aspect processability by adding compositions such as Cu, B.
Description of drawings
The pitting potential figure of the duplex stainless steel that Fig. 1 provides for embodiments of the invention 1;
Fig. 2 is existing 304 stainless pitting potential figure;
Fig. 3 is the stainless pitting potential figure of existing 316L;
Fig. 4 splits figure for the limit of typical duplex stainless steel 2205 steel;
Fig. 5 is that figure is split on the limit of the duplex stainless steel that provides of embodiments of the invention 1;
Fig. 6 is the schema that the Ladle bottom blowing adjustment in embodiments of the invention 1 and 2 is handled.
Embodiment
Introduce the realization and the characteristics of technical solution of the present invention in detail below in conjunction with specific embodiment, understand spirit of the present invention and beneficial effect, but but can not constitute any qualification the present invention's practical range to help the reader.
Embodiment 1 (ZP2102)
1, electrosmelting: High Manganese Carbon Steel 30.1ton packs in electric furnace, low manganese carbon steel 31ton, low-phosphorous nickel-chromium pig iron 10.3ton, the nickel-chromium pig iron 28.6ton of middle phosphorus, high carbon ferro-chrome 39ton adds the 500Kg light dolomite simultaneously with the protection body of heater, adds 1600Kg Fe-Si (75%Si) to flux and to improve the bits flowability, in addition, divide 3 times by high hopper input 5815Kg unslaked lime in the stove;
Melting is carried out in energising, after the energising amount reaches 57246KWh, melts operation and finishes substantially, and molten steel (molten soup) amount is 118.8ton, and liquid steel temperature (going out the soup temperature) is 1584 ℃; This moment electric furnace in molten steel component content as the table 1-1 shown in.
In the electrosmelting process,, do not use during batching to contain the higher raw material of S amount for guaranteeing control for the component content of S.
The component content of the molten steel that table 1-1, electrosmelting obtain (weight percent, %)
| Element | ??C | ??Si | ??Mn | ??P | ??S | ??Cr | ??Ni |
| Content | ??2.23 | ??0.66 | ??0.35 | ??0.032 | ??0.034 | ??17.4 | ??1.94 |
2, AOD handles:
Promptly begin the operation of blowing after in the AOD stove, being blended into molten steel.
A, A01 stage (also claiming 1 stage of oxidation promptly to carry out the oxygen decarburization stage)
Drop into light dolomite 750Kg earlier with the protection body of heater;
Be blown into nitrogen and oxygen (wherein, O again
2Amount is 4150Nm
3, the volume ratio of oxygen and nitrogen is O
2: N
2=195: 30; Be blown into O
2The time be blown into N
2, and, N
2Amount can be according to itself and O
2Ratio determine, charge into O in the following step
2And Ar/N
2The time operation with identical here) blow; Cr content is on the low side in the molten steel after the electrosmelting, in converting process, drop into 10946KgCharge Chrome (high carbon ferro-chrome again, contain Cr 60%) additional Cr source, drop into simultaneously 947Kg Cu and 506Kg Fe-Mo (containing Mo 60%) again, be 1740 ℃ of the target temperatures that reach the A01 stage, drop into general carbon cooling block of 5000Kg and 9000Kg CaO; So far the A01 stage feeds intake and finishes, and the liquid steel temperature that obtains is 1743 ℃, and its one-tenth is grouped into content shown in table 1-2.
The component content of the molten steel that obtains after table 1-2, the A01 stage processing (weight percent, %):
| Element | ??C | ??Si | ??Mn | ??P | ??S | ??Cr | ??Ni | ??Mo | ??Cu |
| Content | ??0.48 | ??0 | ??0.24 | ??0.0326 | ??0.03 | ??18.87 | ??1.88 | ??0.24 | ??0.75 |
B, A02-A05 stage (adjust oxygen argon/nitrogen ratio and carry out the oxidation stage of oxygen decarburization)
After the A01 stage finished, the ratio of oxygen and nitrogen/argon gas of constantly adjusting according to the carbon content in the molten steel and temperature was proceeded the operation of blowing, wherein:
A02 stage gas ratio is O
2: N
2=90: 30, be blown into mixed gas, wherein O
2Be 350Nm
3Drop into simultaneously CaO 3500Kg again, with the basicity of control molten steel about 2.2;
A03 stage gas ratio is O
2: N
2=67: 67, be blown into mixed gas, wherein O
2Be 400Nm
3, drop into 5094Kg Fe-Cr simultaneously once more to improve Cr content;
A04 stage gas ratio is O
2: N
2=30: 90, be blown into mixed gas, wherein O
2Be 200Nm
3, in the hope of reaching the purpose of strengthening decarburization, drop into 50Kg Cu and 200Kg Fe-Mo (containing Mo about 60%) simultaneously, the component content of Cu, Mo in the steel is finely tuned.
After the A01-A04 stage finished, the temperature of molten steel was about 1743 ℃, sampling analysis once more, and the component content of molten steel is shown in table 1-3.
The component content of the molten steel that obtains after table 1-3, the A01-A04 stage processing (weight percent, %)
| Element | ??C | ??Si | ??Mn | ??P | ??S | ??Cr | ??Ni | ??Mo | ??Cu |
| Content | ??0.056 | ??0 | ??0.23 | ??0.0328 | ??0.0094 | ??20.02 | ??1.87 | ??0.33 | ??0.78 |
The above-mentioned stage is proceeded the blowing operation in A05 stage after finishing, and wherein, the gas ratio in A05 stage is O
2: Ar=18: 72, be blown into mixed gas, wherein O
2About 300Nm
3
The prepared duplex stainless steel of present embodiment is the steel grade of extremely low S content, after handling through A05, with the molten steel heating deposit, carries out the needed temperature of double slag process operation to reach.
C, reduction phase
Above A01-A05 is the oxidation and decarbonization stage, and C content is reduced to 0.056% from 2.23%, has finished the adjustment of component contents such as Cr, Ni, Mo, Cu in addition, finishes after the above-mentioned steps, and the operation of proceeding to blow mainly comprises following two stages:
Agitation phases: be blown into the about 250Nm of Ar
3
Reduction phase: be blown into the about 750Nm of Ar
3
At reduction phase, drop into a certain amount of Si (with the form input of Si-Mn alloy and Fe-Si alloy), a part is used for reducing the decarburization stage by O
2The metal oxide of oxidation, a part are used for adjusting the component content of the Si in the molten steel, and this stage is dropped into about 2676Kg of Si-Mn alloy and Fe-Si alloy 1882Kg altogether.
According to CaF
2/ CaO=30% calculates, and drops into CaF again
23722Kg; Dropping into Fe-Si after 3 minutes, drop into Al bead 225Kg again and be used to strengthen deoxidation simultaneously, further alloying constituent is adjusted according to the composition in A04 stage at last, drop into Ni 225Kg.
This reduction phase also is the stage of desulfurization for the first time, and to obtain the temperature of molten steel be 1717 ℃ in the thermometric sampling finishing after, and the component content of molten steel is as showing shown in the 1-4.
The component content of the molten steel that table 1-4, reduction phase obtain after handling (weight percent, %):
| Element | ??C | ??Si | ??Mn | ??P | ??S | ??Cr | ??Ni | ??Mo | ??Cu | ??N |
| Content | ??0.014 | ??0.326 | ??1.32 | ??0.032 | ??0.0015 | ??21.54 | ??1.955 | ??0.31 | ??0.745 | ??0.061 |
D, secondary desulfurization stage
For the S content that makes AOD when tapping is lower than 5ppm, on the basis of the desulfurization first time, slag making and drop into CaO, CaF once more
2Carry out the desulfurization second time again:
At first before the secondary desulfuration operations, flow the slag operation earlier, the bits during with first time desulfurization have all flowed as far as possible, in case non-return sulphur;
After the operation of stream slag finishes, entering the temperature rise period, is O with the gas ratio
2: Ar=90: 30, be blown into O
2About 150Nm
3, drop into following raw materials: 3244Kg CaO, 947Kg CaF
2, 545KgFe-Si, 100Kg Al;
Feed intake and enter into the Reduction stage (reduction phase) after finishing once more and be blown into 650Nm
3Ar, for adjusting alloying constituent, drop into 106Kg Ni once more, 82Kg Cu, 353Kg Fe-Cr alloy;
After this discontinuous running finished, the temperature that records molten steel was 1690 ℃, and the molten steel composition content that records of sub-sampling is shown in table 1-5 again.
The component content of the molten steel that table 1-5, secondary desulfurization stage obtain after handling (weight percent, %):
| Element | ??C | ??Si | ??Mn | ??P | ??S | ??Cr | ??Ni | ??Mo | ??Cu | ??N |
| Content | ??0.019 | ??0.476 | ??1.32 | ??0.0327 | ??0.0008 | ??21.47 | ??2.0 | ??0.31 | ??0.79 | ??0.045 |
E, add the nitrogen stage
After desulfurization is finished, add the nitrogen operation, calculate, be blown into N according to adding nitrogen casting yield 95%
2About 150Nm
3
After finishing, confirm in the fire door sampling whether add nitrogen reaches at once, the molten steel composition content that sampling records is shown in table 1-6;
According to table 1-6 result as can be seen, target component is all reached, tapping smoothly, and liquid steel temperature is 1655 ℃.
Table 1-6, add the molten steel that obtains after the nitrogen stage processing component content (weight percent, %):
| Element | ??C | ??Si | ??Mn | ??P | ??S | ??Cr | ??Ni | ??Mo | ??Cu | ??N |
| Content | ??0.020 | ??0.51 | ??1.32 | ??0.0329 | ??0.0005 | ??21.52 | ??2.01 | ??0.31 | ??0.80 | ??0.1686 |
3, Ladle handles (trimming and temperature adjustment)
Ladle handles focuses on adding the B element, and according to determining slag-removing time the duration of pouring, bottom blowing Ar carries out P/P (gas permeable brick) perforate operation then, and thermometric sampling after the perforate determines that according to the sampling composition alloy fine setting kind and input amount adjust.Calculate according to B casting yield 80%, drop into Fe-B alloy 26Kg; For guaranteeing that Ca content reaches below the 20ppm, drop into Ca-Si sheet 394Kg, drop into lime powder Lime then and be incubated, all the other are according to this area treatment process or the strict execution of processing Pattern as shown in Figure 6 commonly used; Thermometric sampling back confirms that upward the temperature (temperature of setting out) of the big bag platform of continuous casting is 1553 ℃, and the component content in the molten steel is shown in table 1-7; So far reach the component content scope of desired duplex stainless steel.
The component content of the molten steel that obtains after table 1-7, Ladle handle (weight percent, %):
| Element | ??C | ??Si | ??Mn | ??P | ??S | ??Cr | ??Ni | ??Mo | ??Cu | ??N | ??B |
| Content | ??0.023 | ??0.59 | ??1.47 | ??0.0335 | ??0.0007 | ??21.50 | ??2.01 | ??0.33 | ??0.78 | ??0.1616 | ??0.0029 |
Embodiment 2
1, electrosmelting: carbon steel 57.3ton packs in electric furnace, low-phosphorous nickel-chromium pig iron 33.3ton, high carbon ferro-chrome 49.9ton adds 500Kg Fe-Si alloy simultaneously to improve the bits flowability, drops into 8662Kg unslaked lime in the stove by high hopper 3 times in batches in addition;
Melting is carried out in energising, after the energising amount reaches 58603KWh, melts operation and finishes substantially, and molten steel (molten soup) amount is 131.1ton, and liquid steel temperature (going out the soup temperature) is 1578 ℃; This moment electric furnace in molten steel component content as the table 2-1 shown in.
In the electrosmelting process,, do not use during batching to contain the higher raw material of S amount for guaranteeing control for the component content of S.
The component content of the molten steel that table 2-1, electrosmelting obtain (weight percent, %)
| Element | ??C | ??Si | ??Mn | ??P | ??S | ??Cr | ??Ni |
| Content | ??1.89 | ??0.16 | ??0.17 | ??0.022 | ??0.034 | ??22.0 | ??1.93 |
2, AOD handles:
Promptly begin the operation of blowing after in the AOD stove, being blended into molten steel.
A, A01 stage
Drop into light dolomite 787Kg earlier with the protection body of heater;
Add nitrogen and oxygen (wherein, O again
2Amount is 3094Nm
3, the volume ratio of oxygen and nitrogen is O
2: N
2=195: 30) blow; Cr content is on the low side in the molten steel after the electrosmelting, in converting process, drop into 4589Kg Charge Chrome alloy again and replenish the Cr source, simultaneously drop into 1138KgCu again, 1200Kg Fe-Mo alloy, and input 167Kg Fe-Si alloy is used for heating up and 5067Kg CaO is used as slag making; So far the A01 stage feeds intake and finishes, and the liquid steel temperature that obtains is 1714 ℃; Obtain the component content of the molten steel of A01 after the stage behind the sampling analysis,, only record C:0.503%, S:0.0218% owing to have pore (Pin Hole) in the sample.
B, A02-A05 stage
After the A01 stage finished, the ratio of oxygen and argon gas/nitrogen of constantly adjusting according to the carbon content in the molten steel and temperature was proceeded the operation of blowing, wherein:
A02 stage gas ratio is O
2: N
2=90: 30, be blown into O
2About 348Nm
3, drop into CaO 3030Kg simultaneously again;
A03 stage gas ratio is O
2: N
2=67: 67, consider that A01 stage C content is that 0.50% summary is high, at general 350Nm
3The basis on increase and to be blown into 250Nm
3, be blown into O
2About 600Nm
3
A04 stage gas ratio is O
2: N
2=30: 90, be blown into O
2About 202Nm
3, to reach the purpose of strengthening decarburization;
Sampling analysis once more after the A04 stage finishes, owing to still have Pin Hole, the component content that obtains in the molten steel is C:0.0592%, S:0.0185%;
The temperature of the molten steel that the process A04 stage obtains is 1760 ℃, and temperature drift drops into general refrigerant 570Kg and cools off;
The above-mentioned stage is proceeded the blowing operation in A05 stage after finishing, and wherein, A05 stage gas ratio is O
2: Ar=18: 72, be blown into O
2About 400Nm
3
The prepared duplex stainless steel of present embodiment is the steel grade of extremely low S content, after handling through A05, with the molten steel heating deposit, carries out the needed temperature of double slag process operation to reach.
C, reduction phase
Above A01-A05 is the decarburization stage, and C content is reduced to 0.0592% from 1.89%, has finished the adjustment of component contents such as Cr, Ni, Mo, Cu in addition, finishes after the above-mentioned steps, and the operation of proceeding to blow mainly comprises following two stages:
Agitation phases: be blown into the about 251Nm of Ar
3
Reduction phase: be blown into the about 889Nm of Ar
3
At this reduction phase, drop into a certain amount of Si (with the form input of Fe-Si alloy), a part is used for reducing the decarburization stage by O
2The metal oxide of oxidation, a part are used for adjusting the component content of Si in the molten steel, and this stage is dropped into the about 3553Kg of Fe-Si alloy altogether.
According to CaF
2/ CaO=30% calculates, and drops into CaF again
24519Kg; Dropping into the Fe-Si alloy after 3 minutes, drop into Al bead 225Kg again and be used to strengthen deoxidation simultaneously, further alloying constituent is adjusted according to the composition in A04 stage at last, drop into Mn 1892Kg.
This reduction phase also is the stage of desulfurization for the first time, and the thermometric sampling obtains the component content of molten steel shown in table 2-2 after finishing.
The component content of the molten steel that table 2-2, reduction phase obtain after handling (weight percent, %):
| Element | ??C | ??Si | ??Mn | ??P | ??S | ??Cr | ??Ni | ??Mo | ??Cu | ??N |
| Content | ??0.010 | ??0.381 | ??1.45 | ??0.025 | ??0.0007 | ??22.55 | ??2.32 | ??0.51 | ??0.706 | ??0.065 |
D, secondary desulfurization stage
For the S content that makes AOD when tapping is lower than 5ppm, on the basis of the desulfurization first time, slag making and drop into CaO, CaF once more
2Carry out the desulfurization second time:
At first before the secondary desulfuration operations, flow the slag operation earlier, the bits during with first time desulfurization have all flowed as far as possible, in case non-return sulphur;
After the operation of stream slag finishes, entering the temperature rise period, is O with the gas ratio
2: Ar=90: 30, be blown into O
2About 802Nm
3, drop into following raw materials: 8621Kg CaO, 2559Kg CaF
2, 345KgFe-Si alloy, 100Kg Al;
Feed intake and enter into reduction phase once more after finishing and be blown into 534Nm
3Ar, for adjusting alloying constituent, drop into 297Kg Cu, 97Kg Mn once more;
After this discontinuous running finished, the temperature that records molten steel was 1690 ℃, and the molten steel composition content that records of sub-sampling is shown in table 2-3 again.
The component content of the molten steel that obtains after table 2-3, the desulfurization stage processing for the second time (weight percent, %):
| Element | ??C | ??Si | ??Mn | ??P | ??S | ??Cr | ??Ni | ??Mo | ??Cu | ??N |
| Content | ??0.026 | ??0.256 | ??1.44 | ??0.0247 | ??0.0005 | ??21.69 | ??2.2 | ??0.49 | ??0.67 | ??0.1362 |
E, add the nitrogen stage
After desulfurization is finished, add the nitrogen operation, calculate, be blown into N according to adding nitrogen casting yield 95%
2About 194Nm
3
After finishing, fire door sampling at once confirms whether add nitrogen reaches, and the molten steel composition content that sampling records is shown in table 2-4;
According to table 2-4 result as can be seen, target component is all reached, tapping smoothly, and liquid steel temperature is 1675 ℃.
Table 2-4, add the molten steel that obtains after the nitrogen stage processing component content (weight percent, %)
| Element | ??C | ??Si | ??Mn | ??P | ??S | ??Cr | ??Ni | ??Mo | ??Cu | ??N |
| Content | ??0.026 | ??0.34 | ??1.48 | ??0.0248 | ??0.0005 | ??21.48 | ??2.22 | ??0.48 | ??0.98 | ??0.1643 |
3, Ladle bottom blowing adjustment is handled
Ladle bottom blowing adjustment is handled focuses on adding the B element, calculates according to B casting yield 80%, drops into Fe-B alloy 53Kg; For guaranteeing that Ca content reaches below the 20ppm, drop into Ca-Si sheet 353Kg, all the other are according to this area treatment process or the strict execution of processing Pattern as shown in Figure 6 commonly used; The temperature of confirming to set out after the thermometric sampling is 1533 ℃, and the component content in the molten steel is shown in table 2-5; So far reach the component content scope of desired duplex stainless steel.
The component content of the molten steel that obtains after table 2-5, Ladle handle (weight percent, %)
| Element | ??C | ??Si | ??Mn | ??P | ??S | ??Cr | ??Ni | ??Mo | ??Cu | ??N | ??B |
| Content | ??0.028 | ??0.54 | ??1.47 | ??0.0243 | ??0.0006 | ??21.48 | ??2.22 | ??0.48 | ??0.81 | ??0.1592 | ??0.0039 |
Related various raw materials in the embodiments of the invention 1 and 2, for example high carbon ferro-chrome, low-phosphorous nickel-chromium pig iron etc., all are field of metallurgy raw materials commonly used, wherein related carbon content, phosphorus content or the like are all within the common scope that adopts in this area, for persons skilled in the art, corresponding raw material and content range all are clearly; In addition, wherein related various operations and processing also can be carried out according to this area mode commonly used.
Performance test:
Solidity to corrosion and hot workability to the duplex stainless steel of different steel grades and the embodiment of the invention 1 preparation are carried out following performance test:
According to the KSD0238 standard, adopting concentration is the critical pitting potential (Pitting Potential) that 3.5%NaCl solution is measured duplex stainless steel of the present invention, 304 steel and 316L steel respectively, and wherein, sample is area 1cm
2, thickness 1mm the round sheet sample, test result is shown in Fig. 1-3 and table 3, wherein Fig. 1-3 is respectively the stainless pitting potential figure of duplex stainless steel, 304 stainless steels and 316L that embodiments of the invention 1 provide, the electromotive force that the shown numerical value of table 3 is added when being meant a specimen current being reached 10 μ A and 100 μ A, the high more explanation resistance to corrosion of potential value is strong more.
According to the shown data of table 3 as can be seen, when electric current reaches 10 μ A and 100 μ A, the electromotive force that the electromotive force that duplex stainless steel added of embodiments of the invention 1 preparation is added on 304 steel and the 316L steel, the duplex stainless steel of this explanation embodiment of the invention 1 preparation has the corrosion resistance nature that obviously is better than 304 steel and 316L steel, can satisfy of the requirement of different environments for use, can substitute 304 steel and 316L steel and use in a lot of fields for Corrosion Resistance of Stainless Steels.The pitting potential value of stainless steel of the present invention, 304 steel and 316L steel is as shown in table 3.
Picture is split on the limit of the duplex stainless steel that typical duplex stainless steel 2205 steel that Fig. 4 and Fig. 5 show respectively and embodiments of the invention 1 are prepared, the limit amount of splitting that can see 2205 steel from figure is about 30-40mm, and the limit amount of splitting of the prepared duplex stainless steel of the embodiment of the invention is about 5-6mm, and the prepared duplex stainless steel of the present invention has very remarkable advantages with respect to 2205 steel aspect hot workability as can be seen.
Table 3
Claims (6)
1. duplex stainless steel, by weight percentage, its one-tenth is grouped into and comprises:
Cr:20.0-22.0%, Ni:1.9-2.3%, Mo:0.2-1.0%, Mn:1.0-2.0%, N:0.1-0.2%, all the other are Fe and inevitable element.
2. duplex stainless steel as claimed in claim 1, wherein, by weight percentage, its one-tenth is grouped into also and comprises: below the S:0.0025%, below the P:0.035%.
3. duplex stainless steel as claimed in claim 1, wherein, by weight percentage, its one-tenth is grouped into also and comprises: below the Si:2.0%.
4. duplex stainless steel as claimed in claim 1, wherein, by weight percentage, its one-tenth is grouped into also and comprises: Cu:0.7-1.0%.
5. duplex stainless steel as claimed in claim 1, wherein, by weight percentage, its one-tenth is grouped into also and comprises: B:0.0028-0.0043%.
6. as each described duplex stainless steel of claim 1-5, wherein, this duplex stainless steel obtains by electrosmelting, the oxygen refining of AOD argon and Ladle Processing of Preparation.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102181609A (en) * | 2011-05-17 | 2011-09-14 | 山西太钢不锈钢股份有限公司 | Desulfurization method for smelting two-phase stainless steel |
| CN102728801A (en) * | 2012-07-12 | 2012-10-17 | 屈志 | Production technology of base stock for stainless steel precision casting |
| CN102943148A (en) * | 2012-11-30 | 2013-02-27 | 张家港浦项不锈钢有限公司 | Method for producing high-purity stainless steel |
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| CN106636862A (en) * | 2016-01-28 | 2017-05-10 | 中原特钢股份有限公司 | Technology for smelting super duplex stainless steel for argon oxygen furnace |
| CN107109603A (en) * | 2014-12-26 | 2017-08-29 | Posco公司 | Yield strength and the excellent super-duplex stainless steel of impact flexibility and its manufacture method |
| WO2017157351A1 (en) * | 2016-03-17 | 2017-09-21 | 周海彬 | Smelting method for niobium-containing inconel alloy |
| CN114916830A (en) * | 2022-04-13 | 2022-08-19 | 广东智科电子股份有限公司 | Control circuit and control method for water heater |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102181609A (en) * | 2011-05-17 | 2011-09-14 | 山西太钢不锈钢股份有限公司 | Desulfurization method for smelting two-phase stainless steel |
| CN102728801A (en) * | 2012-07-12 | 2012-10-17 | 屈志 | Production technology of base stock for stainless steel precision casting |
| CN102728801B (en) * | 2012-07-12 | 2014-06-04 | 屈志 | Production technology of base stock for stainless steel precision casting |
| CN102943148A (en) * | 2012-11-30 | 2013-02-27 | 张家港浦项不锈钢有限公司 | Method for producing high-purity stainless steel |
| CN103469104A (en) * | 2013-08-15 | 2013-12-25 | 甘肃酒钢集团宏兴钢铁股份有限公司 | Boron-containing double phase stainless steel and boron alloyage smelting method thereof |
| CN107109603A (en) * | 2014-12-26 | 2017-08-29 | Posco公司 | Yield strength and the excellent super-duplex stainless steel of impact flexibility and its manufacture method |
| CN106636862A (en) * | 2016-01-28 | 2017-05-10 | 中原特钢股份有限公司 | Technology for smelting super duplex stainless steel for argon oxygen furnace |
| WO2017157351A1 (en) * | 2016-03-17 | 2017-09-21 | 周海彬 | Smelting method for niobium-containing inconel alloy |
| CN114916830A (en) * | 2022-04-13 | 2022-08-19 | 广东智科电子股份有限公司 | Control circuit and control method for water heater |
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